Process Flow
01. Wax pressing
Low-temperature wax is injected into a mold through a wax press under constant temperature and humidity conditions to produce a wax mold with precise dimensions and a smooth surface, laying the foundation for subsequent shell making.
02. Pruning wax group tree
The surface of the wax model is trimmed to remove burrs, flash, and flow marks. Then, multiple qualified wax models are welded onto the pouring cup and runner according to the process design to form a wax tree, ensuring smooth filling of the molten metal and sufficient shrinkage.
03. Dipping and sanding
The wax tree is immersed in a semi-silica sol slurry and coated evenly, then covered with refractory sand. After drying and curing, this process is repeated multiple times to form a complete shell with a certain thickness layer by layer.
04. Dewaxing
The shell is sent into a steam dewaxing kettle, where high-temperature steam completely melts and removes the low-temperature wax inside, forming a cavity inside the shell that matches the shape of the wax model.
05. Roasting
The dewaxed shell is sent to a baking furnace for high-temperature sintering to remove residual wax and volatiles, while improving the shell’s strength and permeability, thus preparing it for casting.
06. Melting and casting
According to the material ratio, stainless steel raw materials are smelted in a medium-frequency induction furnace. After the molten steel is fully refined, it is poured into the baked mold at a uniform speed along the pouring cup at a suitable temperature to ensure complete filling.
07. SPECTRO spectrometer detection
Before casting, samples of molten steel are taken from the furnace front and the material composition is tested using a SPECTRO spectrometer. Only after confirming that the chemical composition meets the corresponding standards can casting be carried out, thus controlling the material qualification rate from the source.
08. Warehousing (warehousing of casting blanks)
After casting and cooling, the casting blanks are removed by shelling, cutting, grinding to remove the gating gates and flash, shot blasting to clean the surface, and after passing inspection, they are put into storage.
09. Machining
According to the drawing requirements, CNC machining centers, CNC lathes and other equipment are used to perform precision machining on the key parts of the casting blank (sealing surfaces, mating surfaces, threads, etc.) to ensure that the dimensional accuracy and geometric tolerances meet the design requirements.
10. Assembly
After machining, the valve body, valve cover, valve stem, ball core and other precision parts are cleaned and assembled according to the assembly process specifications, and the sealing parts and fasteners are put in place to complete the assembly of the whole valve.
11. Quality Inspection
The assembled valves undergo shell strength and sealing performance tests (air pressure or water pressure), and key dimensions and appearance quality are verified to ensure that each product is qualified before it can be released.
12. Shipping
Products that pass quality inspection are cleaned and rust-proofed, packaged according to customer requirements (wooden boxes, pallets, or export packaging), affixed with nameplates and certificates of conformity, and then shipped to the designated location via logistics.
